Video coding standards include H.264/AVC (Advanced Video Coding). ISO/IEC MPEG and ITU-T VCEG have established Joint Collaborative Team on Video Coding (JCT-VC) to achieve a compression ratio exceeding that of H.264/AVC and have started discussing a next-generation system referred to as High Efficiency Video Coding (HEVC).
There are various types of terminals that decode and play coded video, for example, a terminal capable of playing video at a high resolution or a terminal capable of playing video only at a low resolution. Thus, there is a need for a scalability extension coding system capable of playing video at a plurality of resolutions as necessary by partially extracting data from a coded stream. Scalable Video Coding (SVC) is standardized as scalability extension in H.264/AVC.
In conventional video coding standards including H.264/AVC, SVC, and MPEG-2, the macroblock that is a unit for coding has a fixed size.
For HEVC that is in the process of design, making the block size that has been fixed in and before H264/AVC variable is under consideration. Specifically, the block size of a unit CU (Coding Unit) with which the coding is performed is managed using a tree structure such that the number of pixels on a side of the block is a power of two. Coding or decoding is performed using the block size of an arbitrary layer (see NPL 1).